Phloroglucinol derivatives



Patented Apr. 22, 1952 'STATESAJPATENT OFFICE I PHLOROGLUCINOLDERIVATIVES Max N. Huffman, Dallas, Tex.

- are-Drawing. Application May 2,1949,

. Serial No. 91,015

f .1 Claim. (owed-613) This invention relates to new chemical compoundsand more particularly-tonew derivatives of phloroglucinol. g Y IPhloroglucinol, having the structural formula no on and some of itsderivatives, are known, but they have had no particular interest asgermicides. The present invention involves the discovery that certainnew derivatives of phloroglucinol have unexpected utility as'germicidesfor antiseptic and therapeutic use.

The compounds of the invention can be represented by the structuralformula:

R o- -R1 In this formula R. is a radical containing from four to sixteencarbon atoms, at least one of which is an aliphatic carbon atomconnected through the ether linkage to the benzene nucleus. If R isalkyl, it can be a straight chain, or a secondary It has been found thatthe group is from four to six carbon atoms long.-

The alkyl group constituting the. radical R can contain reactive groupssuch as hydroXyl, carboxyl and halogen components. For example, it

can be carboxymethyl, glyc'eride, or chloroalkyl. -l. .Or, to theradical B. may be attached a cyclic group, either directly. to orthrough an ether linkage, so that R, for example, is benzyl orphenoxyethyl. B may, as Well, be alkoxy-alkyl such as ethoxyethyl.

In general terms therefore, the substituent at the 5-carbon of thephloroglucinol nucleus is connected through its other linkage to thebenzene ring. The R of this substituent can be alkyl or aralkyl. solongas an aliphatic carbon thereof is connected to this ether oxygen.

The R in the above formula can be hydroxy, alkoxy, acyioxy, amino, NHalkyl, or -NI-I acyl. If it is hydroxyl, it is apparent that theresulting compound is a mono-ether of phloroglucinol, and that if it isalhoxy, the resulting compound is a (ii-ether of phleroglucinol. .Itmaybe ohserved here that if R is alkoxy, any of the radicals fallingwithin the definition of R as set forth above, may constitute the alkylportion of R,

If R is acyloxy, the acidradical may be from an aliphatic, an aromatic,or a heterocyclic acid.

.Thus the resulting ester may be that of acetic acid, benzoic acid ornicotinic acid. Further, the

component may be butyryl, benzoyl, or nicotinyl.

Furthermore, in this respect, the acyl group may be of a sulfonic acidas sulfanilyl, succinyl, or may be guanyl.

It will therefore be seen that the invention contemplates certain ethersof phloroglucinol, an ester of phloroglucinol, or of phloramine. In thecase of the ethers, both monoand di-ethers are contemplated and in allinstances an aliphatic carbon is immediately connected to the etheroxygen. 4 In the case of ether derivatives of phloramine, this amino onthe benzene nucleus may be alkyl or acyl substituted.

The monoalkyl ethers of phloroglucinol were generally prepared bydissolving the anhydrous phloroglucinol and 2 moles of the alcohol indicxane (freshly-distilled from sodium), cooling the the flask wasclosed with a glass stopper, allowed to stand in the ice-bath two tothree hours, and then allowed to remain at room temperature in the darkfor a period of one to two weeks. The dialkyl ethers were obtained in asimilar fashion except that the anhydrous phloroglucinol was dissolvedin a great excess of the alcohol.

After the reaction time had ended, the reaction mixture was taken up inethyl ether or benzene, and the organic phase washed well with water.The solvent was evaporated and unreacted alcohol removed in vacuo; theresulting residue was distilled or recrystallized depending upon theparticular compound. Purification was often facilitated by distillationprior to crystallization. Both fmonoand di-ethers can be isolated fromthe reaction in. which the phloroglucinol was dissolved in an excess ofthe alcohol. Int-he case of octyl In general, this condition ofreactionsfavors the formation of (ii-ether. The mono-ether was separated fromdi-ether by reason of its solubility in potassium carbonate solution,and insolubility in petroleum ether. If this separation is not performedbefore distillation, a mixture of both monoand di-ethers distils,although separation is facilitated if the residue from initialextraction is distilled prior to alkali separaton. Due to thesusceptibility of the mono-ethers to air in alkaline solution, nearlyall of the mono-ethers were prepared without alkali extraction.Recrystallization from aqueous alcohol and from benzenepetroleum etherwas used for the mono-ethers,'the' di-ethers being pure after distillingtwice at high vacuum. The di-ethers were generally oils at roomtemperature.

To obtain the mono-ethers of an ester: of phloroglucinol, the mono-etherobtained as above was generaly reacted with an anhydride of the acid.Recovery of the desired product is carried out by selective extractionand evaporation.

The mono-ether obtained as above described was used to obtain thecorresponding derivative of phloramine. .Suitable procedure is outlinedin the following examples dealing with specific compounds of thischaracter. From other examples will be evident the derivation ofcompounds in which the amino radical on the benzene nucleus is alkyl oracyl substituted.

The character of the compounds of the inven' tion and the procedures forobtaining them will be further explained by the following examples:

Example 1 Phloroglucinol mono-n-amyl ether. Anhydrous phloroglucinol(75.6 g., 0.3 mole) was dissolved in a mixture of n-amyl alcohol (105.6g., 0.6 mole) and dioxane (200 ml, which had been freshly distilled fromsodium). This solution was I cooled in an ice-bath and saturated withanhydrous hydrogen chloride. The reaction mixture was allowed to standin the ice-bath for two to three hours; then, at room temperature forten days in the dark. -It was taken up in other (3500 ml.), washed fourtimes with water (1500 ml.) and taken to dryness, finally removingunreacted alcohol in vacuo. The residue was distilled in high vacuum ata: bath temperature of 130-140 at a pressure of three to four microns asread on a Stokes version McLeod gauge. The distillate aftercrystallizing once from benzene and petroleum ether, was pure enough foruse in subsequent reactions. Three recrystallizations from a mixture ofbenzene and petroleum ether ive compound of melting point 86-87%, The

yield was 36.2 g. (30.7%).

been cooled, the contents were taken upin H20 (150 ml.) and acidifiedwith concentrated hydrochloric acid. This mixture was extracted oncewith ether (500 ml.) and the ether washed with H20 (350 ml). The etherphase was then extracted three times with 3 KHCO; (350 ml. portions),and the combined bicarbonate phases acidified at once with concentratedhydrochloric.

acid and extracted with ether (750 ml). This other was washed twice withwater (500 m1. portions), dried over sodium sulfate, and evaporated togive 2.1 g. (96%) of crystalline material. The crystalline residue wasrecrystallized four times from ether-cyclohexane to give a constantmelting material. The 2,6-dihydroxy-4-n-amyloxy benzoic acidcrystallizes in fine needles which decompose at 134-134.5 with evolutionof gas.

The phloroglucinol mono-n-amyl ether of Example 1 may also be convertedto a diacetate or similar di-ester. To obtain the diacetate,phloroglucinol mono-n-amyl ether (2 g., 0.01 mole) was dissolved inacetic anhydride (20 ml.) and heated on the steam-bath for two hours.The mixture was then cooled, diluted with 1-120 ml.) and placed in theice-box. The oil which separated was washed several times with water bydecantation and then dried in vacuo over KOH and H2804. The dried oilwas twice distilled in a high vacuum. The colorless diacetate distils ata bath temperature of at 225 microns. The yield was 2.0 g. (71%). Usingbenzoyl chloride, a dibenzoate of the monoamyl ether was obtained in theform of fine needles melting at 73.

Example 2 Deltc-chlorobutyl mono-ether of phloroglw cinol.Anhydrousphloroglucinol (6.3 g., 0.05 mole) was dissolved in a mixture oftetrahydrofuran (7.2 g., 0.1 mole) and dioxane (20 m1, freshly distilledfrom sodium). After cooling in an ice-bath, the solution was saturatedwith anhydrous hydrogen chloride; then, allowed to stand at roomtemperature for one week. The reaction mixture was dissolved in benzene(1000 ml.), washed with water (750 and two 500 m1. volumesrespectively). The benzene was removed by evaporation and the residuecovered with petroleum ether (50 ml.). After decantation of the solvent,the residual oil was dissolved in benzene, treated with charcoal, andprecipitated with petroleum ether. The compound, after severalrecrystallizations, melted at 77-785". It crystallized in square platesas a monohydrate. The crude yield was 3.0 g. (25.6%).

Anal. Calcd. for C10H1504C1I Cl, 15.11.

Found: 01, 15.16, 15.02.

Example 3 Mono-cetyl ether of phloroglucinol.Anhydrous phloroglucinol(3.2 g., 0.025 mole) and cetyl alcohol (12.1 g., 0.05 mole) wasdissolved in dioxane (40 ml.). Anhydrous hydrogen chloride was bubbledthrough the solution with occasional cooling to prevent heating and themixture allowed to stand at room temperature for seven days. Thereaction mixture was taken up in benzene (750 ml.) and washed with water(500 Example 4 M ono-epsz'lon-chloroamyl ether ofphloroglucinol.-Anhydrous phloroglucinol (6.3 g., 0.05

'mole) and pentamethylene chlorohydrin (15 gm,

.1 mole excess) was dissolved in dioxane (20 ml., freshly distilled fromsodium). .The solution was cooled in an ice-bath and saturated withanhydrous hydrogen chloride. After standing in the ice-bath for two tothree hours, it was allowed to stand at room temperature for seven days.The reaction mixture was taken up in benzene (1000 ml.) and washed fourtimes with water (750 ml. portions). The benzene was evaporated and theunreacted chlorohydrin removed in vacuo. The residue was covered withpetroleum ether (50 ml.) and placed in the refrigerator. Sincepurification by recrystallization was difficult, the 1.7 g. of materialwas taken up in ether and extracted with 3% potassium bicarbonate. Onacidification of the carbonate layer and extraction with ether followedby two recrystallizations from a mixture of benzene and petroleum ether,the mono-ether was obtained. The yield was 0.60 g. (5%) of materialmelting at 61-6152 which would melt considerably higher on furtherpurification.

Anal.-Calcd. for CnHnO-iCl: Cl, 14.25. Found: Cl, 14.20, 14.33.

Example 5 D-i-n-amyZ-ether of phZorogZucinoZ.-Anhydrous phloroglucinolg, 0.03 mole) was dissolved in n-amyl alcohol (100 ml). After saturationwith anhydrous hydrogen chloride with cooling in an ice-bath, thesolution was allowed to stand at room temperature for seven days.

The reaction mixture was taken up in benzene (500 m1.) and washed threetimes with water (250 ml. volumes). After evaporation of the benzene andremoval of unreacted alcohol in vacuo, the di-ether was obtained bytwice extracting the residue with refluxing petroleum. ether (250 ml.volumes). The petroleum ether extracts were combined, washed three timeswith 3% potassium carbonate (250 ml. volumes). The potassium carbonateextracts were discarded and the petroleum ether extracted four timeswithN sodium hydroxide (250 ml. volumes). On acidification withhydrochloric acid an oil separated which was extracted with ether (750ml. and 500 ml. portions). The ether was washed with water and removedby evaporation. The residue was distilled twice in high vacuum. Theproduct distilled at a bath temperature of 100 at a pressure of 56microns. A yield of 4.3 was obtained.

AnaZ.Calcd. for CieHasOs! C, 72.14; H, 9.34. Found: C, 72.06, 71.98; H,9.45, 9.53.

To further characterize the product of Example 5, the tributyl ether wasprepared as follows: Phloroglucinol dibutyl ether (1.2 g., 0.005 mole)was dissolved in n-butyl chloride (5 ml.) and treated with potassiumhydroxide dissolved. in butanol ('7 ml, of a stock solution prepared bydissolving 5.0 g. KOH in 55 ml. butanol) and the mixture refluxed over afree flame for thirty minutes. The reaction mixture was taken up inbenzene (200 ml.) and washed four times with water (100 m1. portions).The benzene was taken to dryness and unreacted alcohol removed in vacuo.The residue was taken up in petroleum ether (250 ml), washed four timeswith N sodium hydroxide (150 ml. portions), then with three portions ofwater (200 ml. each). The residue after evaporation of the petroleumether was distilled in high vacuum. The yield was 0. 8 grams of an oildistilling at a bath temperature of 105-110" at 150 microns pressure.(The unreacted dibutyl ether was quantitatively recovered.)

AnaZ.--Calcd. for CisHsoosi C, 73.42; H, 10.27. Found: C, 73.35, 73.45;H, 10.17, 10.25.

Example 6 3 n-amylory-5-hydroacyphenoryacetic acid. Phloroglucinolmonoamyl ether (4.0 g., 0.02 mole) and chloracetic acid (1.8 g., 0.02mole) were dissolved in 30% sodium hydroxide (15 ml.) and refluxed for1.5 hours over a micro gas flame. The mixture was acidified withconcentrated hydrochloric acid while still hot, cooled and the reactionmixture taken up in ether (250 ml.) The ether was washed two times withwater and then extracted twice with 3% sodium carbonate (250 ml.portions). Strong acidification of the combined carbonate layersresulted in the separation of the product an oil. The acidified layerplus oil was extracted twice with ether and the combined ethers washedtwo times with H2O. Evaporation of the ether yielded an oil whichrecrystallized from a mixture of benzene'and petroleum ether. Severalrecrystallizations from aqueous ethanol gave 1.2 g. (24%) of colorlessmaterial melting at 139.

Example 7 l-n-amylory- 3 -hydroxy-5-methozcyzencena- Phloroglucinolmono-n-amyl ether (4.6 g.) was dissolved in absolute methanol (25 ml).The solution was saturated with anhydrous hydrogen chloride while beingcooled in an ice-bath. The reaction mixture was allowed to stand fornine days at room temperature and then taken up in benzene (400 ml.) andthe benzene washed two times with water (250 m1. portions) The desiredcompound was then extracted from the benzene by shaking three times withN sodium hydroxide (250 ml. portions). Acidification of the combinedalkali phases caused the separation of the product as an oil which wasdissolved by twice extracting the mixture with ether (first 500 ml. then250 ml.). The ether, after having been washed twice with water, wasevaporated to give 2.5 g. of an oil. This oil, which failed tocrystallize, was dissolved in a mixture of benzene ml.) and petroleumether (200 m1.) and washed two times with 3% potassium carbonate (250ml.) to remove any unreacted monoether. The organic phase, after washingwith water, was evaporated to dryness and the resulting oil dissolved inpetroleum ether (50 ml.). The solution was treated with charcoal,filtered, and the filtrate evaporated to about 5 ml. After a period inthe refrigerator, this solution deposited crystals. The product wastwice recrystallized from a mixture of cyclohexane and petroleum etherafter which it melted at 35.

Example 8 Phloroglucinol mono-n-amyl et'hermononicotinate.-Phloroglucinol monoamyl ether (1.9 g., dried by benzenedistillation) and nicotinic anhydride (2.3 g.) was dissolved in drybenzene (25 1111.). The reaction mixture was refluxed on a steam-bathfor four hours during which time it was protected from atmosphericmoisture by means of a drying tube. (The reaction mixture assumed acanary yellow color.) After cooling, the reaction mixture was dissolvedin ether (450 ml.) and filtered free of insoluble nicotinic acid. Theethereal filtrate was then washed four times with 3% potassium carbonate(250 ml. portions) and then washed three times with water (250 ml.portions). Evaporation of the ether yielded an oil which did notcrystallize. This oil was then taken up in benzene (250 ml.) and thelatter extracted three times with 6 N hydrochloric acid. Neutralizationof the combined hydrochloric acid extracts with solid potassiumcarbonate yielded an oil which was extracted with ether (500 ml). Theother solution was washed twice with water, dried over sodium sulfateand the ether removed by evaporation. V The resulting oil upondistillation at 160-165 at 30 microns gave 2.0 g. (66%) of oilydistillate.

Example 9 1-(3-amylomy 5 hydroxyphenoxy) 3-chlo1'0- propanol-2.-Thiscompound is easily prepared by heating together molecular proportions ofphloroglucinol monoamyl ether and epichlorohydrin, since the epoxy groupreacts preferentially. Phloroglucinol monoamyl ether (3.9 g.) andepichlorohydrin (1.8 g.) were heated on a steambath without a solventfor 7 to 8 hours. The mixture was then dissolved in ether (100 ml.) andthe ether washed three times with 3% potassium carbonate and then, twotimes with water. After evaporation of the ether, the excessepichlorohydrin was removed at reduced pressure. The residual oil wasrecrystallized several times from a mixture of benzene and petroleumether. The compound was twice recrystallized from benzene (treated withcharcoal each time). The product separated in glistening plates whichmelted at 138-139, the yield was 2.2 g. (31%).

From Examples 1 through 9 will be evident other examples of analogousmonoand di-ethers. Thus by selection of the corresponding alcohol andfollowing the general procedure of Example 1 or 3, the desired etherwill be obtained. By using a secondary or "branched chain alcohol, thesecondary or iso ether derivative will be obtained. Other di-ethers canbe produced according to Example 5, and mixed di-ethers can be obtainedsimilar to the procedure of Example 7.

By using benzoic anhydride or other aromatic anhydrides and proceedingaccording to Example 8, other mono-ether, mono-ester derivatives ofphloroglucinol are obtainable. It will here be recognized that by firstpreparing the proper mono-ether as the starting compound according tothe method explained above, the desired ester of this mono-ether will beobtained. Similarly, other examples of mono-esters of aliphatic acidswill be evident from Example 8.

The production of mono-ether derivatives of phloramine and N-alkyl andN-acyl phloramine will be clear from the following examples. Mention mayfirst be made, however, of the followin dihydroxy, N-acyl derivatives ofphloramine to show the general characteristics of phloramine.

N(3,5-dihydroxyphenyl)-nicotinamide is prepared as follows: Phloramine(1.2 g., 0.02 mole, dried in a vacuum desiccator) was dissolved withwarming in dioxane ml., freshly distilled from sodium) After the aminehad dissolved, nicotinic anhydride (2.3 g.) was added and the reactionmixture allowed to stand at room temperature for one day.Crystallization occurred soon after admixture of the reactants. Theproduct was recrystallized four times from a mixture of dioxane andpetroleum ether. The final yield was 2.0 g. (83.3%) of material whichdarkened at 195 and melted with decomposition at 197-198. Analyticaldata shows the compound to be a monohydrate.

Anal-Calcd for cizHizOiNz': N, 11.29. Found: N, 11.15, 11.09.

N-(3,5-dihydroxyphenyl) -butyramide was prepared as follows: Dryphloramine (2.4 g., 0.02 mole) was dissolved in dioxane (40 m1, freshlydistilled from sodium) by warming on a steambath. After all thephloramine had dissolved, butyric anhydride (3.2 g.) was added and themixture allowed to stand at room temperature for one hour. The mixturewas then cooled in iccbath and the white solid which separated wascollected by filtration and washed with cold dioxane. Afterrecrystallizing three times from dioxane with concurrent treatment withcharcoal, there remained 3.8 g. (quantitative) of glistening crystalswhich melted at 179.

Anal.Calcd. for CioHlsOsNZ N, 7.18. Found: N, 7.30, 7.23.

Example 10 Phloramine monoamyl ether.-The amination oi phloroglucinolmono-amyl ether was accomplished by utilization of the Buchererreaction. Phloroglucinol mono-amyl ether (7.8 g.), ammonium chloride(2.1 g.), sodium bisulfite (4.4 g.) and 28% ammonia ml.) were placed ina Monel-metal bomb. The sealed bomb was heated in an oil bath for sixhours at The bomb contents were dissolved in ether (500 ml.) and thenextracted with dilute hydrochloric acid (two 250 ml. portions and 100ml. portion respectively). The combined aqueous extracts were madealkaline with solid potassium carbonate whereupon the amine separated asa crystalline solid. After cooling by addition of ice, the solid wasremoved by filtration and washed Well with ice water. Afterrecrystallizing three times from a mixture of benzene and petroleumether, with attendant treatment with charcoal, there remained 5.1 g.(65.4%) of glistening leaflets which melted at 104.5.

AnaZ.-Calcd for CnHrzOzN: C, 67.65; H, 8.78; N, 7.17. Found: C, 67.66,67.70; H, 8.72, 8.74 N, 7.25, 7.19.

Example 11 N (3 n amylory 5 hydroryphenyl) nicotinamirle. Phloraminemono-amyl ether (1.9 g., 0.01 mole) and ni-cotinic anhydride (2.3 g.)were both dried in vacuum desiccator over sulfuric acid and potassiumhydroxide and then dissolved in dry benzene (75 ml.). This reactionmixture was refluxed on a steam-bath for thirty minutes during whichtime it became a white paste. After evaporating the benzene, the residuewas twice recrystallized from aqueous alcohol finally from absoluteethanol. The yield was 28 g. (almost theoretical) of white crystalswhich melted at 189-189.5.

Anal-Calcd for C17H20N203; N, 9.33. N, 9.20, 9.29.

Found:

Example 12 N (3 n amylory 5 hydroryphenyl) succinamic acid.Phloramine(1.95 g., 0.01 mole) and succinic anhydride (1.0 g., 0.01 mole) wasdissolved in dry chloroform (35 ml.) and the resulting solution heatedat reflux for fifteen minutes. A few minutes after refluxing con1-menced, a precipitate began to separate and eventually the whole mixturebecame a white paste. The reaction mixture was then cooled and placed ina refrigerator for one day.

The white precipitate was removed by filtration and washed well withcold chloroform. The solid (2.5 g.) was dissolved in ether (168 ml.) andextracted with 3% sodium bicarbonate (100 ml). The aqueous phase wasmade acid to Congo red paper with acetic acid and a small amount ofhydrochloric acid, whereupon crystallization tool: place at once. Afterchilling in the refrigerator, the crystals were removed by filtrationand without drying dissolved in methanol. The solution was treated withcharcoal, filtered, treated with water, and concentrated tosupersaturation. After recrystallizing once more from aqueous methanoland twice from aqueous ethanol, the glistening plates melted at99-100.5. The yield was quantitative.

Anal.Calcd. for C15H21O5N: N, 4.74. Found: N, 4.63, 4.68.

Example 13 N (3 n amylowy 5 hydromyphenyl) sulfiam'la'mide. Phloraminemono-amyl ether (1.0 g., 0.005 mole) was dissolved in pyridine (3' ml);then with swirling 4-acetylaminobenzenesulfonyl chloride (1.2 g.) wasgradually added with occasional cooling in ice-bath. After all the acidchloride was added, the reaction mixture was heated with swirling on awater-bath at '70- 80 for forty-five minutes. The reaction mixture wastreated with dilute hydrochloric acid until no further precipitationoccurred. The oil which separated was removed by decantation anddissolved in alcohol. After treating the solution with charcoal andfiltering, water was added and the resulting solution concentratedtoturbidity on a steam-bath. The solid that separated on cooling 5.60.Found: N, 14.54; S, 5.57."

From Example 10, other mono-ethers of phloramine will be evident andconsequently it would be repetitive to set them forth specifically.

Any of the mono-ethers contemplated above, such as are evident fromExamples 1 to 4 inclusive, may be used in place of the mono-amyl etherof Example 10. In like manner, instead of using ammonia as in Example10, the use of an alkyl amine will produce the corresponding N-alkylderivative of a mono-ether phloramine.

Other examples of the production of a desired N acyl derivative of amono-ether phloramine will be evident from Examples 11 to 14 inclusive.

' Thus, it will be evident that other aliphatic or in the refrigeratorwas recrystallized three times from aqueous ethanol. The yield ofmaterial melting at 130-131" was 1.2 g.

The above acetyl derivative (.7 g.) was dissolved in a mixture ofconcentrated hydrochloric acid (5 ml.), water (5 m1.), and ethanol (2ml.) and then heated at reflux for five hours. After cooling, solidpotassium carbonate was added until the solution was slightly akaline;then the mixture cooled in the refrigerator. The compound separated asan oil and then solidified. After twice recrystallizing from aqueousethanol with attendant treatment with charcoal, colorless platelets wereobtained -which melted at 137-138". The yield was 0.5 g. (49.1%).

AnaZ.Calcd. for CrzH22N2O4S: N, 8.00; S, 9.15. Found: N, 8.08; S, 9.23.1

Example 14 (3 amyloxy 5 hydromy) phenylguanidine.-- After unsuccessfulattempts to effect the condensation of phloramine mono-amyl ether withmethyl-isothiourea sulfate using absolute ethanol or water as solvents,the guanyl derivative was finally prepared by fusing the two solids:

. aromatic acids or their anhydrides, may, for example, be used toobtain the desired N-acyl comfalling within the above Examples 1 to 14,and

Phloramine monoamyl ether (1.0 g., 0.005 mole) and methyl iso-thioureasulfate (1.4 g.) were homologue and analogues thereof which have beendiscussed, be considered as a part of this disclosure as thoughspecifically set forth.

What is claimed is:

' Phloroglucinol derivatives having the formula:

in which R is an alkyl radical containing six carbon atoms.

MAX N. HUFFMAN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,966,635 Marx July 1'7, 1934

